Electrical relay



June 20, 1939. F. AGNEW I 2,162,903

ELECTRICAL RELAY FiledAug. 19, 1936 2 Shets-Sheet 1 52 b2sulalio12.

I Norm NV 2 9: ew 2. BY I f HLS ATTORNEY Patented June 20, 1939 UNITED STATES PATENT OFFICE ELECTRICAL RELAY of Pennsylvania Application August 19, 1936, Serial No. 96,831

6 Claims.

My invention relates to electrical relays.

I will describe one form of relays embodying my invention, and will then point out the novel features thereof in claims.

A feature of my invention is the provision of novel and improved means for varying the reluctance of the magnetic circuit of electrical relays and which means permits the parts to be rigidly clamped in their adjusted positions. A further feature of the invention is the provision in relays of the type here contemplated of novel and improved armature and contact mechanism.

In the accompanying drawings, Fig. 1 is a rear elevation of a relay embodying the invention. Fig. 2 is an inverted plan view with the cover in section of the relay of Fig. 1, and Fig. 3 is a side elevation partly in section of the relay. Fig. 4

is a fragmental View of Fig. 2 showing the relationship of the armature and pole faces. Figs. 5, 6 and 7 are views of the adjustable spacer which forms a part of the magnetic circuit of the relay of Figs. 1, 2 and 3. Fig. 8 is a modified form of the spacer of Figs. 5, 6 and 7. mg. 9 is a diagrammatic view of a battery charging system in which the relay of Figs. 1 to 8 is employed. In each of the several views like reference characters designate similar parts.

Referring to Figs. 1, 2 and 3, a top plate A of non-magnetizable material has projecting therethrough two magnetizable core pieces BI and B2,

and has secured on its underside an armature supporting plate Cl which is of non-magnetizable material such as brass. The top plate A is preferably of molded insulating material, the core pieces BI and B2, as well as the plate Cl, being molded therein. The top plate A is provided with terminal posts such as terminal post T for the purpose of making connection with outside circuits, and has secured to its underside by screws 32 and 33 a glass cover plate P for enclosing the armature and contact mechanism of the relay. The core pieces BI and B2 terminate on the underside of the top plate A in pole pieces Bi! and B!?., respectively, and are provided at their upper or free ends with outwardly extending ends Bl3 and BM, respectively. A depending L-shaped pole piece extension Di of magnetizable material is secured to pole piece Bl! by screws and 5 (see Fig. 4), and a similar pole piece extension D2 is secured to pole piece BlZ by screws 6 and i. The pole piece extensions DI and D2 are spaced apart and are disposed with respect to each other so that the right-hand face of pole piece extension DI as viewed in Figs. 2 and 4, and the left-hand face of pole piece extension D2 are in the same plane. A bracket 8 of non-magnetizable material is secured to the plate C! by screws 9 and It, the bracket 8 being centrally located between the pole pieces BH and BIZ, as well as between the pole piece extensions D! 5 and D2.

An armature I3 is pivotally mounted in bracket 8 by means of a center bearing pin I30 which passes through the armature and is fastened thereto, as by rivets. The pin l3c is journaled in 10 bracket 8 at H and I2 by suitable bearings or trunnions to bring the pin in the same plane as the aforementioned pole faces of the pole piece extensions Di and D2. The armature I3 is provided with two portions Ba and [3b which are 15 laterally disposed to opposite sides of its center line. With the armature I3 thus constructed and mounted it is in magnetic relationship with the pole piece extensions Di and D2 for attraction between the faces lSd and I36 of the arma- 20 ture and the respective adjacent faces of pole piece extensions DI and D2. The movement of armature l3 toward the pole piece extensions Di and D2 is limited by a core pin 38, which pin also secures to the armature a counterweight 39 to 25 be referred to later.

A series of insulation strips [4 are fastened by screws I5 t0 the surface of the pole piece extension Di opposite its face exposed to the armature l3. Two contact fingers l6 and Ill are 3 mounted in these insulation strips spaced apart so as to be insulated from each other. The heel of contact finger I6 is connected by a flexible connector l8 to a terminal post S in the top plate A, and the heel of the contact finger H is con- :35 nected by a flexible connector 9 to a terminal post C in the top plate A. The contact fingers l6 and H are provided with contacts 20 and El, respectively, and the parts are so proportioned that the contacts 20 and 2! normally engage to 0 complete the circuit connection therethrough. The outer end of contact finger I6 is provided with a U-shaped extension Ilia which extends around in front of an insulation strip 22 secured to the armature 13 as by rivets All, and which 45 rivets may extend through the armature l3 and also serve as core pins therefor.

It is clear that magnetic attraction between pole piece extensions DI and D2 and the armature 53 causes the armature to rotate in a counter- 50 clockwise direction as viewed in Fig. 2. When the armature i3 is thus rotated the strip 22 engages the extension Ilia of contact finger I6 and operates the contact finger to break engagement between contacts 20 and 2|. 55

A biasing spring 23 is hooked at one end to a plate 24 secured to armature l3 by the same rivets 40 securing the insulation strip 22 thereto, and is hooked in its other end to a plate 25 secured to the outer end of the insulation strips M by being interposed under the heads of the screws [5. The spring 23 is adjusted to draw armature l3 in a clockwise direction, as viewed in Fig. 2, against the attractive force of the pole piece extensions DI and D2, the movement of armature l3 by spring 23 being limited by a stop plate 26 which is also fastened in the insulation strips.

l4. The counterweight 39 securedto armature I3 is so proportioned and positioned as to balance the insulation strip 22 and the spring securing plate 24, the armature l3 being thus balanced with respect to its center pin I30.

Magnetic flux is supplied to the core pieces BI and B2 and hence through the pole pieces B1 and BM to the pole piece extensions DI and D2, by a winding W mounted on a core or back strap 21 of magnetizable material. The back strap 2? is fastened to the outwardly extending ends Bl3 and BM of the core pieces BI and 132 by means of two bolts 23 and 2%. Two spacers 3a; and 3E are interposed between the magnet core or back strap 27 and the ends B13 and BM, respectively. When winding W is energized sufficiently the attraction of armature [3 toward the pole piece extensions D! and D2 overcomes the force of the spring 23 and armature i3 is rotated. about its center pin until the core pins engage the pole piece extensions, the contact finger it being engaged by the strip 22 for operating the contact 2G2! to its open position. The parts are so proportioned that the strip 22 does not engage the contact finger [6 until the armature !3 has nearly completed its movement and the air gaps are short with the result that the contact 20-21 is operated with a snap action. Furthermore, since the armature I3 is balanced about its center pin and is biased by the spring 23, when movement of armature i3 is once started, .it makes its complete movement without hesitation and chattering of the contact 2tl-2i at the critical operating value of the energizing current is avoided. Again, spring 23 exerts a greater pull on armature l3 when the armature is over against the pole piece extensions DI and D2 and hence is effective to operate the armature back to its normal position when the winding W-is deenergized. That is, armature I3 is retained in its normal position until the pickup value of current is supplied to the Winding W and when this value of current is reached full movement of the armature I3 is effected without hesitation. When winding W is deenergized the force of spring 23 is such as to operate armature l3 back to its normal position where contact 202i is closed. Consequently, a relay constructed with contact and armature mechanism embodying my invention operates the contact without chattering at the critical value of current.

Under certain conditions it is desirable to vary the operating characteristics of a relay so as to operate the circuit controlling contact for different values of energizing current. To accomplish this result without adjustment of the armature and contact mechanism the spacer 3B is provided with a non-magnetizable member 34, a mag netizable member 35 and an elongated hole 36, see Figs. 5, 6 and 7. Fig. 5 shows the spacer 38 positioned to give maximum reluctance between back strap 2'! and the end Bl3 of core piece BI, and Fig. 6 shows the spacer 30positioned to give minimum reluctance between the back strap 21 and the end Bl3 of the core piece. Positions of spacer 30 in between the positions illustrated in Figs. 5 and 6 will give varying degrees of reluctance to the magnet circuit, the tapered portion 31 of non-magnetizable member 34 being provided to give a uniform adjustment. It is clear that by loosening bolt 28, the spacer 30 can be quickly set to any of its positions. and the parts can be tightly clamped in their adjusted positions by tightening the bolt 28 to withstand vibration and rough handling. It is apparent that the spacer 30 may be constructed with a notch 46 in one surface as shown in Fig. 8 and one edge of which notch may have a tapered surface 41. With the spacer 30 thus constructed the reluctance between the back strap 2'! and the core piece B l may be varied by adjusting spacer 30 to bring more or less of the notch 46 between the back strap 21 and the core piece Bl. The spacer 3! may be similar in construction to spacer 30, but ordinarily it would be nonadjustable and of magnetizable material.

Many places where relays embodying my invention will be useful will suggest themselves. Fig. 9 shows a system of battery charging employing such a relay. A battery 4! is charged from a source of alternating current not shown through a transformer Tl, a rectifier 42 and a resistor 43. Contact 2[l2l of the relay of Figs. 1 to 8 forms a shunt path around resistor 43. The winding W of the relay is connected across the battery over a circuit controlling contact 44 and in series with a resistance 45. Consequently, battery 4| is charged at a relatively high rate when contact 202! is closed and the resistance 43 is shunted, and is charged at a lower rate when contact 2fl-2l is operated to an open position and resistor 43 is interposed into the circuit. The spacer 30 of the relay Would be set so that the fully charged voltage of battery 4! when applied to winding W creates sufiicient magnetic flux to attract the armature 13 of the relay and to operate contact 2ll2l to its open position with the result that the battery is charged at the lower rate, and which rate is sufficient to maintain the battery 4| at a fully charged condition. When a load is placed on the battery 4! the contact 44 would be operated and the relay deenergized, contact 44 .being. operated by the same apparatus that governs the load on the battery 4|. With the relay deenergized and contact 202i closed the higher charging rate is established until the load demand ceases and the batteryis again brought back to its fully charged condition.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing .from the spirit and scope of my invention.

Having. thus described my invention, what I claim is:

l. A relay comprising two fixed magnetizable core pieces terminating in spaced pole faces, a movable armature bridging the pole faces, a single electromagnet having a winding and a magnetizable core passing through the winding and adapted to bridge the free ends of said core pieces, a spacer interposed between the free end of one of the core pieces and the core of the electromagnet, said spacer constructed with a magnetizable member having a slotted hole formed therein and a non-magnetizable member secured to one face thereof, and a clamping bolt adapted to pass through aligned holes in the magnet core and said core piece as well as the slotted hole of said spacer, whereby the reluctance of the magnetic circuit of the relay is varied by adjusting the position of the spacer to bring more or less of the non-magnetizable member between said cores and the parts are rigidly clamped in their adjusted positions.

2. A relay comprising two fixed magnetizable core pieces terminating in spaced pole faces, a movable armature bridging the pole faces, a single electromagnet having a winding and a magnetizable core passing through the winding and adapted to bridge the free ends of said core pieces, a spacer interposed between the free end of one of the core pieces and the core of the electromagnet, said spacer constructed with a magnetizable member having a slotted hole formed therein and an inset of non-magnetizable material secured on one face thereof and said inset having one end tapered, and a clamping bolt adapted to pass through aligned holes in said cores as well as the hole of the spacer whereby the reluctance of the magnetic circuit is varied by adjusting the spacer to bring more or less of the inset between said cores and the parts are rigidly clamped in their adjusted positions.

3. A relay comprising two fixed magnetizable core pieces terminating in spaced pole faces, a movable armature bridging the pole faces, a single electromagnet having a winding and a magnetizable core passing through the winding and adapted to bridge the free ends of said core pieces, a spacer interposed between the free end of one of the core pieces and the core of the electromagnet, said spacer constructed with a magnetizable member having a slotted hole formed therein and a tapered notch formed on one surface, and a clamping bolt adapted to pass through aligned holes in the magnet core and said core piece as well as the hole of said spacer whereby the reluctance of the magnetic circuit of said relay is varied by adjusting said spacer to bring more or less of the notch between said cores and the parts are rigidly clamped in their adjusted positions.

4. In a relay haw'ng an electromagnet provided with a pair of pole pieces in spaced relation and formed with pole piece extensions and having an armature pivotally mounted between the pole pieces for magnetic attraction between the opposite faces of its two end portions and pole faces formed on said pole piece extensions and which armature is spring biased away from the pole faces to a position of a predetermined air gap the combination comprising, an insulated actuating member secured to the back of the armature on its end portion adjacent a first one of the pole piece extensions, a series of insulation strips secured to the second one of the pole piece extensions on its surface opposite its pole face, two flexible contact fingers mounted in said insulation strips spaced apart and having their outer ends adjacent the end portion of the armature carrying said actuating member, contacts secured one on each of said contact fingers adaptable to at times engage for completing a circuit connection between the contact fingers, and an extension memher formed on the outer end of one of said contact fingers for operatively cooperating with said actuating member with lost motion to operate the contact mounted on that contact finger with respect to the contact mounted on the other contact finger when the air gap between the armature and the pole faces is short and operation of said contacts is effected by a. snap action.

5. In a relay having an electromagnet provided with a pair of pole pieces in spaced relation and formed with pole piece extensions and having an armature pivotally mounted between the pole pieces for magnetic attraction between the opposite faces of its two end portions and pole faces formed on said pole piece extensions and which armature is spring biased for movement away from said pole faces the combination comprising, an insulation member secured to the back of the armature on its end portion adjacent a first one of the pole piece extensions, a series of insulation strips secured to the second one of the pole piece extensions on its surface opposite its pole face, a stop plate mounted in said insulation strips and having its outer end positioned to limit movement of the armature by said spring bias, two

flexible contact fingers mounted in said insulation strips so as to be insulated from each other and having their outer ends adjacent the armature end portion to which the insulation member is secured, contacts mounted one on each of said contact fingers and disposed to engage when the armature is moved against said stop plate, and a U-shaped extension formed on the outer end of one of said contact fingers to extend around the end of the insulation member for causing said contacts to break engagement when the armature has nearly completed its movement as it is attracted toward said pole faces.

6. In a relay having an electromagnet provided with a pair of .pole pieces in spaced relation and formed with pole piece extensions and having an armature pivotally mounted between the pole pieces for magnetic attraction between the oppo site faces of its two end portions and pole faces formed on said pole piece extensions and which armature is spring biased for movement away from said pole faces the combination comprising, an insulation member secured to the back of the armature on its end portion adjacent a first one of the pole piece extensions, a series of insulation strips secured to the second one of the pole piece extensions on its surface opposite its pole face, a stop plate mounted in said insulation strips and having its outer end positioned to limit movement of the armature by said spring bias, a flexible contact finger mounted in said insulation strips and having its outer end formed to operatively cooperate with said insulation member with lost motion for operation without hesitation of the contact finger when the armature has nearly completed its movement as it is attracted toward said pole faces, and a weight member secured to the armature on its end portion adjacent said second one of the pole piece extensions to coun terbalance said insulation member to avoid when the electromagnet is partially energized chattering of said contact finger due to mechanical shock.

NORMAN F. AGNEW. 

